const renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth,window.innerHeight);
document.body.appendChild( renderer.domElement );

const camera = new THREE.PerspectiveCamera( 45,window.innerWidth/window.innerHeight, 1,500);
camera.position.set(0,0,100);
camera.lookAt(0,0,0);

const scene = new THREE.Scene();
const material = new THREE.LineBasicMaterial({color:0x0000ff});

const points = [];
points.push(new THREE.Vector3(-10,0,0));
points.push(new THREE.Vector3(0,10,0));
points.push(new THREE.Vector3(10,0,0));

const geometry = new THREE.BufferGeometry().setFromPoints(points);

const line = new THREE.Line(geometry,material);

scene.add(line);
renderer.render(scene,camera);
